Topological Synthesis of Single D.O.F. Variable Topology Mechanisms
Date Issued
2005
Date
2005
Author(s)
LEE, Szu-Hung
DOI
en-US
Abstract
A variable topology mechanism is a mechanism which is capable of changing its topological characteristics during motion. The differences of variable topology mechanisms between stages are caused by the changes of variable kinematic joints. By changing its topological characteristic, the variable topology mechanism can achieve different motion requirements in different stages.
In this thesis, the topological synthesis of single D.O.F. variable topology mechanisms is performed. There is only one input in single D.O.F. variable topology mechanisms discussed in this thesis, and the input motion remains the same between different stages.
According to the motion description and compatibility analysis for two-stage latch mechanisms and the Geneva mechanism, the characteristics of variable topology mechanisms are investigated. It is shown that the joint located between two adjacent joints with changing relative motion is a variable kinematic joint. All variable kinematic joints in a variable topology mechanism should change their operating space for the same plane. There should be an intersection line or an overlap plane between operating spaces of two adjacent joints. There should be an intersection line or an overlap plane between the operating space of a variable kinematic joint at one of the stages and the follow-up stage.
With characteristics of variable topology mechanisms, the conceptual design procedure can be conducted. By specifying motion requirements, the variable topology mechanism can be determined to be a planar or a spatial mechanism at each stage. A joint can be verified as a variable kinematic joint or a non-variable kinematic joint according to the relative motion of the attached links. The operating space of a non-variable kinematic joint can be determined by motion requirements, but it is necessary to consider the characteristics. The operating spaces of variable kinematic joints attached to the ground at the first stage can be determined by motion requirements. The operating spaces at the following stages can be determined according to the motion requirements and the compatibility between stages. The operating spaces of other variable kinematic joints at every stage can be determined by motion requirements and the compatibility between adjacent joints. The compatibility of change in operating space of all variable kinematic joints should be checked. Then the joint types of all joints can be specified, and existing designs are checked. After checking existing designs, the new designs are embodied. At last, the design of two-stage latch mechanisms is presented as the design example.
Subjects
機構
可變拓樸機構
可變運動對
Mechanism
Variable topology mechanism
Variable kinematic joint
Type
thesis